Medical instrument

Abstract

A medical instrument in the form of an endoscopic shank instrument includes an actuation element which is axially displaceable in a shank. Two lever arms are pivotably articulated in a manner distanced to one another and are positioned at a proximal side of the shank. The lever arms form part of a grip part. The lever arms are coupled in movement to the actuation element and are coupled directly to one another.

I claim: 
     
       1. A medical instrument in the form of an endoscopic shank instrument comprising:
 an actuation element ( 18 ) axially displaceable in a shank; 
 two lever arms ( 28 ) pivotably articulated in a manner distanced to one another, the lever arms positioned at the proximal side of the shank and forming part of a grip part ( 4   a ,  4   b ), the lever arms ( 28 ) being coupled in movement to the actuation element ( 18 ) and directly coupled in movement to one another; 
 rolling surfaces rolling on one another and being formed on sides of the lever arms ( 28 ) which face one another, each rolling surface having a groove arranged on an outer side thereof; and 
 a spherical widening ( 22 ) formed on the actuation element ( 18 ), and engaging into the grooves formed on the rolling surfaces. 
 
     
     
       2. The medical instrument according to  claim 1 , wherein the rolling surfaces are designed in a toothed manner. 
     
     
       3. The medical instrument according to  claim 1 , wherein the actuation element ( 18 ) is led between the rolling surfaces. 
     
     
       4. A medical instrument in the form of an endoscopic shank instrument comprising:
 an actuation element ( 18 ) axially displaceable in a shank; 
 two lever arms ( 28 ) pivotably articulated in a manner distanced to one another, the lever arms positioned at the proximal side of the shank and forming part of a grip part ( 4   a ,  4   b ), the lever arms ( 28 ) being coupled in movement to the actuation element ( 18 ) and directly coupled in movement to one another; and 
 rolling surfaces rolling on one another and being formed on sides of the lever arms ( 28 ) which face one another, wherein each rolling surface is formed of two parts arranged adjacent to each other in a direction of a pivot axis of each lever arm ( 28 ), wherein teeth are formed on a first part offset by a tooth gap width or tooth thickness with respect to teeth formed on a second part. 
 
     
     
       5. The medical instrument according to  claim 4 , wherein in each case two cog segments ( 30 ,  30 ′) form the rolling surfaces of the lever arms ( 28 ), and wherein all cog segments ( 30 ,  30 ) are designed in a constructionally equal manner. 
     
     
       6. The medical instrument according to  claim 5 , wherein the cog segments ( 30 ,  30 ′) have asymmetrical teeth. 
     
     
       7. The medical instrument according to  claim 5 , wherein each cog segment ( 30 ,  30 ′) comprises two teeth ( 36 ,  36 ′) and two tooth gaps ( 38 ,  38 ′). 
     
     
       8. The medical instrument according to  claim 5 , wherein the cog segments ( 30 ,  30 ′) enclose an angle of 65°. 
     
     
       9. The medical instrument according to  claim 5 , wherein the cog segments ( 30 ,  30 ′) are integrated in the grip parts ( 4   a ,  4   b ).